1. Field of the Invention
The present invention is directed towards a medical instrument of the type structured for use in laparoscopic and/or endoscopic surgery such as, but not limited to, a trocar assembly which includes an elongated shaft having a penetrating tip formed on one end thereof. The penetrating tip includes an exterior surface configuration structured to facilitate the forming of an access opening in bodily tissue in a manner which requires a minimum application of an inwardly directed, linear pushing force on the instrument, but rather, which is more responsive to a back and forth or “reciprocal” twisting motion. The configuration of the penetrating tip is at least partially characterized by a perpendicular cross-section of the exterior surface having a substantially elliptical configuration along at least a majority of the tip.
2. Description of the Related Art
In the medical field there are numerous instruments specifically designed to penetrate bodily tissue so as to provide access to internal body cavities or organs. More specifically, a preliminary procedure during the performance of surgery is the creation of an access opening into the body cavity at a predetermined surgical site. In the past, such access openings were formed by the creation of substantially large incisions through the body wall or outer tissue. The size of an incision would depend on the type of surgery, and accordingly, the surgical instruments involved. On completion of the surgical procedure, the large incision would be closed using conventional techniques. However, due to the traumatic nature of such open surgical procedures, the period of time required for the patient to completely heal was significant. In addition, the pain or discomfort during the recuperative period was a serious problem.
Because of the above noted disadvantages, attempts have been made, which were specifically directed towards new surgical procedures as well as instruments utilized in the support of such procedures. More recently, it has become quite common to employ an alternative type of surgery known as laparoscopic and/or endoscopic surgery, wherein one or more small openings, utilizing appropriate penetrating instruments, are formed in a patient's abdomen typically, to provide access into the intended body cavities wherein surgery on a targeted organ or organs may take place. Unlike the large incision required during open surgery, the much smaller access openings facilitate healing following the surgery and as expected, result in significantly less discomfort to the patient.
Depending on the type of laparoscopic surgery being performed, the instrumentation used to form the one or more small access openings may vary. However, common to such medical penetrating instruments is the provision of a sharpened or otherwise configured penetrating tip. By way of example, instrumentation utilized in the performance of laparoscopic surgery are commonly referred to as trocar devices or trocar assemblies. In conventional fashion, a trocar assembly normally includes a trocar sleeve or cannula and an obturator to which the penetrating tip is attached. Utilizing such instrumentation, access is gained to a body cavity or organ by penetrating the bodily tissue defining the exterior wall of the cavity, in order that laparoscopic surgery may be performed.
The obturator, serving as the penetrating instrument, passes along or is positioned within the lumen of the cannula or trocar sleeve. The penetrating tip is formed on the distal end of the obturator and is forced through the skin until entry to the body cavity has been established. The trocar sleeve, is then forced through the perforation, formed by the obturator and the obturator is withdrawn, leaving the trocar sleeve or cannula as an access passage to the intended body cavity or organ. In related laparoscopic or endoscopic surgical techniques, the penetrating instrument may be used with the trocar sleeve or surgical access cannula or may be used as a “stand alone” device to puncture through the skin and underlying bodily tissue. A small access opening is thereby formed and a separate access cannula, catheter or other surgical instrument is inserted into communication with the now accessed body cavity or organ.
The aforementioned, substantially conventional, medical penetrating instruments normally include a penetrating tip having a sharpened point spaced distally from a base which is connected to one end of the obturator or penetrating instrument. Also, the conventional structure of such penetrating tips typically include either a conical or a multi-sided, substantially pyramidal configuration. The design and structuring of penetrating tips for the type of medical instruments described herein is/are important for the efficient formation of the small access opening, as set forth above. However, such penetrating tips should efficiently and cleanly create the access opening in a manner which serves to at least partially dilate or enlarge the opening, as the shaft of the obturator or other penetrating instrument passes through the bodily tissue. It is, of course, equally important that a minimal amount of damage, in terms of severing or cutting, be done to the contiguous body tissue surrounding the access opening during the initial penetration, as well as the enlargement of the access opening, as the penetrating instrument is positioned into direct communication with the intended body cavity or organ.
Accordingly, there is a need in the field of medical instrumentation for an instrument which may be used independently or which may be associated with a trocar assembly and associated components such as, but not limited to, a trocar sleeve, etc. Any such an improved instrument would preferably be designed to include an improved penetrating tip which is structured to facilitate the smooth and/or clean formation of a small access opening through the puncturing of the body wall. The penetrating tip should preferably include an exterior surface, as well as a distal extremity or apex, and a base which are cooperatively structured and efficiently configured. The structuring of these components should be such as to effectively enlarge the access opening, as the penetrating instrument is advanced therethrough into communicating relation with a predetermined body cavity or organ. Further, the disposition, dimension, configuration and overall structure of any such inventive penetrating tip should be such as to form the access opening without causing any unnecessary or inadvertent cutting, severing or like damage to the outer tissue being penetrated or to the internal organs, once the penetrating tip enters the intended body cavity.